Speaker
Description
We investigate the collision energy dependence of the average transverse energy < (dE_t)/(dy)> at midrapidity registered at midrapidity (|y|<0.5) for identified particles (φ , K+, K- and K mesons) produced in central Au+Au and Pb+Pb collisions over a broad energy range from RHIC to LHC (39 GeV –5020 GeV). Resonances like φ and K have different hadronic cross sections, masses and lifetimes and can be used to study the properties and evolution of the hot and dense QGP medium produced in high energy nucleus-nucleus collisions. Of a peculiar interest is the mechanisms of production of these particles, containing one strange quark.
We present in this report our results of calculations of the average transverse energy at midrapidity using the published data on particle density < (dN)/(dy) > and the mean transverse momenta<p_t> for φ, K+, K- and K* mesons formed in very central (0-5%) Au+Au and Pb+Pb collisions. We found that, similar to our previous studies for φ and K mesons and Ω hyperons[1,2], the collision energy dependence for each particle species is well described by a power-law function of the form ~ Q(sNN)n , Our primary discovery is that the power-law exponent – n, is statistically indistinguishable for all studied particles, from light pions to multi-strange Ω-hyperons. This universal behavior leads to an important property: the ratios of the average transverse energy densities of particles produced in very central nucleus-nucleus collisions are practically constant from RHIC to LHC.
We discuss this observed energy independence of ratios of transverse energies within the framework of the multipomeron exchange model [3]. This interpretation is aimed to check the hypothesis of a possible common underlying production mechanism and provides a method to estimate the fundamental efficient quark-gluon string tension parameter (teff) of the model.
The authors acknowledge Saint-Petersburg State University for a research project 103821868.
1) Shaposhnikova, O., Marova, A. & Feofilov, G.," Open and Hidden Strangeness with Kaons and φ-Mesons in Bjorken Energy Density Approach for Central Collisions from SPS to LHC". Phys. Part. Nuclei 55, 1134–1139 (2024). https://doi.org/10.1134/S10637796247008492).
2) Shaposhnikova O., MarovaA., Feofilov G., "Open and hidden strangeness in central A+A collisions: ratios of the average transverse energy density for ϕ mesons and Ω hyperons in the range \sqrt(s_NN) = 39 GeV - 2.76 TeV", submitted 28.04.2025 to Physics of Atomic Nuclei, ISSN: 1063-7788.
3) Kovalenko, V., Feofilov G., Puchkov A., Valiev F., " Multipomeron Model with Collective Effects for High-Energy Hadron Collisions". Universe 2022, 8, 246.
